Recently, a light emitting diode (LED) is widely used as a light emitting device.
The LED is used for various fields such as a light source of a display device, a lighting apparatus that can replace a fluorescent lamp or an incandescent electric lamp, and a light source used for an automobile.
The LED can be manufactured to emit light of various colors such as red, yellow, green, and blue. White light can be emitted using a phosphor or combining color light emitted from a plurality of LEDs.
Particularly, a light emitting diode emitting white light can be used for various fields, so lots of studies on a light emitting device of a good efficiency are under progress.
Generally, to realize white light in a light emitting device, the light emitting device is formed by combining an LED primarily emitting light in a blue wavelength and a phosphor excited by the light in the blue wavelength emitted from the LED to emit excited light in a yellow wavelength. In the light emitting device using this method, white light realization of the light emitting device is greatly influenced by the efficiency of a phosphor layer including the phosphor.
For example, light emitted from the LED and/or excited light excited by light emitted from the LED are frequently not emitted to the outside from the light emitting device but disappear inside the light emitting device due to a difference in the refractive index between a material forming the LED and air outside the light emitting device, so that light efficiency of the light emitting device is reduced.
Therefore, it is required to allow light emitted from the LED and/or excited light excited by light emitted from the LED to be effectively emitted from the light emitting device.